Multi-source filter and filtering method based on h.264 de-blocking

Abstract

A multi-source filter based on H.264 de-blocking includes the following units. A quantization parameter (qP) calculation unit receives an image data and calculates a qP. A boundary strength (bS) calculation unit receive the image data and calculates a bS. A block detector receives the image data and determines whether the image data falls in the block boundary. An image edge detector receives the image data and determines whether it is not belonged to an image edge region. An enabling unit receives the qP to determine whether to enable a de-blocking filtering operation. A determining unit filters the image data to output a new image data when determines that the image edge is not at the block boundary and the filtering operation is required.

1 . A multi-source filter based on H.264 de-blocking, comprising:
 a first switch unit, for selecting to receive an original quantization parameter (qP) provided by a decoder or a calculated quantization parameter (qP′);   a second switch unit, selecting to receive an original boundary strength (bS) provided by the decoder or a calculated boundary strength (bS′), wherein the first switch unit and the second switch unit simultaneously select the original quantization parameter and the original boundary strength, or simultaneously select the calculated quantization parameter and the calculated boundary strength;   a quantization parameter calculation unit, receiving an image data input thereto and calculating the calculated quantization parameter;   a boundary strength calculation unit, receiving the image data and calculating the calculated boundary strength;   a block detector, receiving the image data and outputting a block detecting value when determines that the image data falls in a block boundary region;   an image edge detector, receiving the image data and outputting a non-edge detecting value when determines that the image data is not belonged to an image edge region;   an enabling unit, connected to the first switch unit to receive the original quantization parameter or the calculated quantization parameter, for comparing the original quantization parameter or the calculated quantization parameter with a threshold value, so as to determine whether or not to output a filter enabling value;   a determining unit, receiving the block detecting value, the non-edge detecting value and the filter enabling value, and outputting an enabling value according to at least one of the block detecting value, the non-edge detecting value and the filter enabling value; and   a filter, connected to the second switch unit, for receiving the enabling value, the image data, and the original boundary strength or the calculated boundary strength transmitted by the second switch unit, so as to perform a filtering operation to the image data according to the original boundary strength or the calculated boundary strength, and output a processed image data.   
     
     
         2 . The multi-source filter based on H.264 de-blocking as claimed in  claim 1 , wherein if the first switch unit transmits the original quantization parameter, the determining unit outputs the enabling value only according to the filter enabling value. 
     
     
         3 . The multi-source filter based on H.264 de-blocking as claimed in  claim 1 , wherein if the first switch unit transmits the calculated quantization parameter, the determining unit outputs the enabling value only when the block detecting value, the non-edge detecting value and the filter enabling value are all in an enabling state. 
     
     
         4 . The multi-source filter based on H.264 de-blocking as claimed in  claim 1 , wherein the quantization parameter calculation unit comprises:
 a first variance calculation unit, performing a variance calculation on n adjacent pixel values of a first side according to an assumed block boundary, so as to obtain a first variance;   a second variance calculation unit, obtaining n adjacent pixel values of a second side according to the assumed block boundary to perform the variance calculation, so as to obtain a second variance;   a maximum value obtaining unit, obtaining a greater value from the first variance and the second variance; and   a value scaling unit, scaling the greater value to output the calculated quantization parameter,   wherein n is not less than 3.   
     
     
         5 . The multi-source filter based on H.264 de-blocking as claimed in  claim 4 , wherein the variance calculation is a high-pass filter calculation. 
     
     
         6 . The multi-source filter based on H.264 de-blocking as claimed in  claim 4 , wherein n=4. 
     
     
         7 . The multi-source filter based on H.264 de-blocking as claimed in  claim 1 , wherein the boundary strength calculation unit comprises:
 a luminance shielding estimation unit, obtaining a first luminance resolution value and a second luminance resolution value corresponding to two pixel luminance values of two adjacent pixels of an assumed block boundary;   a minimum value obtaining unit, obtaining a smaller value from the first luminance resolution value and the second luminance resolution value;   a difference calculation unit, calculating a difference value of the two pixel luminance values; and   a logarithm calculation unit, calculating the calculated boundary strength according to the difference value and the smaller value.   
     
     
         8 . A multi-source filter based on H.264 de-blocking, comprising:
 a quantization parameter calculation unit, receiving an image data input thereto and calculating a quantization parameter according to a first analysis rule;   a boundary strength calculation unit, receiving the image data and calculating a boundary strength according to a second analysis rule;   a block detector, receiving the image data and outputting a block detecting value when determines that the image data falls in a block boundary region;   an image edge detector, receiving the image data and outputting a non-edge detecting value when determines that the image data is not belonged to an image edge region;   an enabling unit, receiving the quantization parameter and comparing the quantization parameter with a threshold value, so as to output a filter enabling value;   a determining unit, receiving the block detecting value, the non-edge detecting value and the filter enabling value, and outputting an enabling value when the block detecting value, the non-edge detecting value and the filter enabling value are all in an enabling state;   a filter, receiving the enabling value, the image data, and the boundary strength, and performing a filtering operation to the image data according to the boundary strength, so as to output a processed image data.   
     
     
         9 . The multi-source filter based on H.264 de-blocking as claimed in  claim 8 , wherein the quantization parameter calculation unit comprises:
 a first variance calculation unit, obtaining n adjacent pixel values of a first side according to an assumed block boundary to perform a variance calculation, so as to obtain a first variance;   a second variance calculation unit, performing the variance calculation on n adjacent pixel values of a second side according to the assumed block boundary, so as to obtain a second variance;   a maximum value obtaining unit, obtaining a greater value from the first variance and the second variance; and   a value scaling unit, scaling the greater value to output the quantization parameter,   wherein n is not less than 3.   
     
     
         10 . The multi-source filter based on H.264 de-blocking as claimed in  claim 9 , wherein the variance calculation is a high-pass filter calculation. 
     
     
         11 . The multi-source filter based on H.264 de-blocking as claimed in  claim 9 , wherein n=4. 
     
     
         12 . The multi-source filter based on H.264 de-blocking as claimed in  claim 8 , wherein the boundary strength calculation unit comprises:
 a luminance shielding estimation unit, obtaining a first luminance resolution value and a second luminance resolution value corresponding to two pixel luminance values of two adjacent pixels of an assumed block boundary;   a minimum value obtaining unit, obtaining a smaller value from the first luminance resolution value and the second luminance resolution value;   a difference calculation unit, calculating a difference value of the two pixel luminance values; and   a logarithm calculation unit, calculating the boundary strength according to the difference value and the smaller value.   
     
     
         13 . A quantization parameter generation circuit, adapted to a H.264 image processing, and comprising:
 a first variance calculation unit, performing a variance calculation n adjacent pixel values of a first side according to a designated block boundary, so as to obtain a first variance;   a second variance calculation unit, performing the variance calculation on n adjacent pixel values of a second side according to the designated block boundary, so as to obtain a second variance;   a maximum value obtaining unit, obtaining a greater value from the first variance and the second variance; and   a value scaling unit, scaling the greater value to obtain a quantization parameter,   wherein n is not less than 3.   
     
     
         14 . The quantization parameter generation circuit as claimed in  claim 13 , wherein the variance calculation is a high-pass filter calculation. 
     
     
         15 . The quantization parameter generation circuit as claimed in  claim 13 , wherein n=4. 
     
     
         16 . A boundary strength generation circuit, adapted to a H.264 image processing, comprising:
 a luminance shielding estimation unit, obtaining a first luminance resolution value and a second luminance resolution value corresponding to two pixel luminance values of two adjacent pixels of an assumed block boundary;   a minimum value obtaining unit, obtaining a smaller value from the first luminance resolution value and the second luminance resolution value;   a difference calculation unit, calculating a difference value of the two pixel luminance values; and   a logarithm calculation unit, calculating a boundary strength according to the difference value and the smaller value.